INVESTIGADORES
SAAVEDRA Maria Lucila
congresos y reuniones científicas
Título:
GENOMIC ANALYSIS OF VITAMIN B12 (COBALAMIN) BIOSYNTHETIC CLUSTER IN Lactobacillus coryniformis CRL 1001
Autor/es:
CAROLINA TORRES; VERONICA VANINI; GRACIELA FONT DE VALDEZ; FERNANDO SESMA; LUCILA SAAVEDRA; MARÍA PÍA TARANTO
Lugar:
Mar del Plata
Reunión:
Congreso; X Congreso de Microbiologia General; 2014
Resumen:
Vitamin B12 (cobalamin-CBL) is one of the most complex non-polymeric macromolecules and is synthesized only by some bacteria and Archaea, although relatively few can synthesize it de novo. Humans need this vitamin as cofactor for different cellular reactions. B12 deficiency can cause different pathological manifestations that affect the hematopoietic, neurological and cardiovascular system, amongst others. Therefore it is important to adequate B12 dietary intake, with meat foods and their derivatives such as milk, eggs or pharmaceuticals products. Previous findings in our lab demonstrated that cell extract of Lactobacillus (L.) coryniformis CRL 1001 is able to correct the coenzyme B12 requirement of Salmonella enterica serovar Typhimurium (metE cbiB) in minimal medium. Considering these evidence, the aim of this study was the sequencing of genome and the molecular characterization of CBL biosynthesis in the CRL1001 strain. L. coryniformis CRL 1001 genome was sequenced by a whole-genome shotgun (WGS) strategy with an Ion Torrent personal genome machine based upon libraries created using NEBNext DNA library kits (MR DNA, Shallowater, TX). Genomic analyses were done using the RAST annotation Server, Blast algorithms, ISGA and KEGG databases. The draft genome sequence consists of 2,829,178 bases with a mean GC content of ?%. A total of 3,341 coding sequences (CDS) and 82 structural RNAs (58 tRNAs) were predicted. Additionally, there are 332 RAST subsystems represented in the chromosome, which represent only 44% of the sequences assigned. RAST analysis evidenced the presence of at least 30 genes involved in the CBL biosynthesis in CRL1001 strain. Preliminary comparative studies among vitamin B12 producer strains demonstrated that, as in other genera, the genetic organization of cob operon is conserved in this strain and these genes are adjacent to the pdu operon and pocR gene. The hem genes (hem A, C, B y L) present in L. coryniformis CRL 1001 genome are located among cob operon in similar way to L. reuteri strains and in anaerobic microorganisms such as Clostridium, suggesting a putative common ancestor in the anaerobic cobalamin biosynthetic pathway in this strain. The knowledge of cob genes and their regulation in vitamin producer lactic strains constitutes an interesting biotechnological alternative for developing fortified foods with proven effectiveness.